; Descriptors: URANIUM 234; Subject Codes 10/5/1147 RADIOACTIVITY; GEOLOGY; URANIUM 238; (NSA): PHYSICS WATER (Item 147 from file: ROCKS; SEA; SOILS; URANINITES 109) 214772 NSA-17-004718 t NATURAL VARIATIONS IN THE RATIO OF USsup 2346 TO USsup 23$$sup '8$ Thurber, D.L. Columbia Univ., Palisades, N.Y. Lamont Geological Observatory Publication Date: Note: nd 11 p. ’ IAEA Preprint SM-33/12; TID-17377£ For presentation at the IAEA Symposium on Radioactive Dating, 1962 held at Athens, Greece, November 19-23, Journal Announcement: NSA17 Document Type: Book Language: English For presentati on at the IAEA Symposium on Radioactive Dating, held at Athens, life Greece, November 19-23, (250,000 years) 1962. Although U/sup 234/ has a good half for Pleistocene dating, it was previously ignored because no reasonable mechanism for separation from its parent, U/sup 238/ seemed to exist. The report of enrichment of U/sup 234/ in ground waters and secondary minerals by several Russian workers suggests that this possible chronometer be seriously considered. Using alpha spectrometry the U/sup 234//U/sup 238/ activity ratios of carbonate deposits from two glacial lake basins and a few selected marine samples were measured. Modern ocean water has an A/sup U/sup 234//A/sup U/sup 238/ ratio of 1.15 based on four samples from the Pacific and Atlantic. Since the experimental error on these measurements is about two per cent, the residual anomaly should be detectable in samples up to one million years old, providing a dating method through a period of time not heretofore covered by physical means. Unrecrystalized coral from an Eniwetok drill hole gave ages based on U/sup 234/U/sup 238/ ratios in agreement with other methods. The oldest sample, dated as Miocene by paleontologists, was in radioactive equilibrium. Thus the method appears valid in at least one case. Six samples from the Lake Lahontan basin have a U/sup 234//sup 238/ ratio of about 1.5, and six from Lake Bonneville have values of about 2.0. This anomaly should be detectable in samples less than 1.5 million years old. Although the available data on these two glacial lake basins suggest some variations in the ratio with different lake levels owing to changing drainage patterns, the system does not appear complicated. It appears therefore that the anomalous A/sup U/sup 234//A/sup U/sup 238/ ratios in integrating basins such as the ocean, and playa lakes, provide a very promising geologic dating method for the period from 100,000 years to 1,000,000 years in both continental and marine systems. (auth) Descriptors: AGE ESTIMATION; ALPHA SPECTROMETERS; CARBONATES; DEPOSITS; DISTRIBUTION; ENRICHMENT; ERRORS; GEOLOGY; GROUND WATER; HALF-LIFE; MEASURED VALUES; MINERALS; QUANTITY RATIO; SEA; URANIUM 234 ; URANIUM 238; VARIATIONS; WATER ™ Subject Codes (NSA): GEOLOGY, MINERALOGY, AND METEOROLOGY (Item 148 from file: 109) NSA-17-003202 USE OF A PORTABLE WHOLE-BODY COUNTER TO MEASURE INTERNAL CONTAMINATION IN A FALLOUT-EXPOSED POPULATION Cohn, S.H.; Conard, R.A.; Gusmano, E.A.; Robertson, J.S. Brookhaven National Lab., Publication Date: 1961 Upton, N.Y. 25 p. Primary Report No.: BNL-5974 Journal Announcement: NSA17 Document Type: Report Language: English The Marshallese people of Rongelap Atoll, who were accidentally exposed to fallout in 1954, were the subject of a large scale survey for evaluating radionuclide body burdens in 1961. Experience is described in the use of a portable whole-body gamma counter, with details on measurements made, methods used, and automatic data-handling techniques developed for 9003b2b 10/5/148 213260